Use of polyalkylene glycol to reduce fuel consumption

ABSTRACT

The use of a polyalkylene glycol of formula HO—(A—O) p —(CH 2 CH 2 —O) m —(A—O) q —H wherein A is a C 3 - to C 20 -alkylene group or a mixture of such alkylene groups, m is a number of from 2 to 100 and p and q are each numbers of from 1 to 100, as an additive in a fuel for reducing fuel consumption in the operation of an internal combustion engine with this fuel.

The present invention relates to the use of a polyalkylene glycol ofgeneral formula I

HO—(A—O)_(p)—(CH₂CH₂—O)_(m)—(A—O)_(q)-H  (I)

wherein A is a C₃- to C₂₀-alkylene group or a mixture of such alkylenegroups, m is a number of from 2 to 100 and p and q are each numbers offrom 1 to 100,

-   -   as an additive in a fuel for different purposes.

The present invention further relates to a fuel composition whichcomprises a gasoline fuel, the polyalkylene glycol mentioned and atleast one fuel additive with detergent action.

The present invention further relates to an additive concentrate whichcomprises the polyalkylene glycol mentioned and at least one fueladditive with detergent action.

It is known that particular substances in the fuel reduce internalfriction in the internal combustion engines, especially in gasolineengines, and thus help to save fuel. Such substances are also referredto as lubricity improvers, friction reducers or friction modifiers.Lubricity improvers customary on the market for gasoline fuels areusually condensation products of naturally occurring carboxylic acidssuch as fatty acids with polyols such as glycerol or with alkanolamines,for example glyceryl monooleate.

A disadvantage of the prior art lubricity improvers mentioned is poormiscibility with other typically used fuel additives, especially withdetergent additives such as polyisobuteneamines and/or carrier oils suchas polyalkylene oxides. An important requirement in practice is that thecomponent mixtures or additive concentrates provided are readilypumpable even at relatively low temperatures, especially at outsidewinter temperatures of, for example, down to −20° C., and remainhomogene-ously stable over a prolonged period, i.e. no phase separationand/or precipitates may occur.

Typically, the miscibility problems outlined are avoided by addingrelatively large amounts of mixtures of paraffinic or aromatichydrocarbons with alcohols such as tert-butanol or 2-ethylhexanol assolubilizers to the component mixtures or additive concentrates. In somecases, however, considerable amounts of these expensive solubilizers arenecessary in order to achieve the desired homogeneity, and so thissolution to the problem becomes uneconomic.

In addition, the prior art lubricity improvers mentioned often have thetendency to form emulsions with water in the component mixtures oradditive concentrates or in the fuel itself, such that water which haspenetrated can be removed again via a phase separa-tion only withdifficulty or at least only very slowly.

WO 99/16849 discloses a complex ester resulting from an esterificationreaction between polyfunctional alcohols and polyfunctional carboxylicacids using a chain stopping agent to form ester bonds with theremaining hydroxyl or carboxyl groups, containing as a polyfunctionalcarboxylic acid component dimerised and/or trimerised fatty acids. Thiscomplex ester is recommended for as an additive, a base fluid or athickener in transmission oils, hydraulic fluids, four-stroke oils, fueladditives, com-pressor oils, greases, chain oils and for metal workingrolling applications.

WO 98/11178 discloses a polyol ester distillate fuel additivesynthesized from a polyol an a mono- or polycarboxylic acid in such amanner that the resulting ester has uncon-erted hydroxyl groups, suchpolyol ester being useful as a lubricity additive for diesel fuel, jetfuel and kerosene.

WO 03/012015 discloses an additive for improving the lubricity capacityof low-sulphur fuel oils, such additive containing an ester of abivalent or polyvalent alcohol and a mixture of unsaturated or saturatedmono- or dicarboxylic acids whose carbon length are between 8 and 30carbon atoms.

It was an object of the present invention to provide fuel additiveswhich firstly bring about effective fuel saving in the operation of aspark-ignited internal combustion engine, and secondly no longer havethe outlined shortcomings of the prior art, i.e. more particularly notremaining homogeneously stable over a prolonged period without any phaseseparation and/or precipitates, poor miscibility with other fueladditives and the tendency to form emulsions with water. In addition,they should not worsen the high level of intake valve cleanlinessachieved by the modern fuel additives.

Accordingly, the use of a polyalkylene glycol of general formula I asdescribed above as an additive in a fuel for reducing fuel consumptionin the operation of an internal combustion engine with this fuel hasbeen found. Preferably, the said use as an additive in a gasoline fuelfor reducing fuel consumption in the operation of a spark-ignitedinternal combustion engine with this fuel or as an additive in agasoline fuel for reduction of fuel consumption in the operation of aself-ignition internal combustion engine with this fuel has been found.

It can be assumed that the cause of the fuel saving by virtue of thepolyalkylene glycol mentioned is based substantially on the effectthereof as an additive which reduces internal friction in the internalcombustion engines, especially in gasoline engines. The reaction productmentioned thus functions in the context of the present inventionessentially as a lubricity improver.

Furthermore, the use of a polyalkylene glycol as described above as anadditive in a fuel for minimization of power loss in internal combustionengines and for improving acceleration of internal combustion engineshas been found.

Furthermore, the use of a polylalkylene glycol as described above as anadditive in a fuel for improving the lubricity of lubricant oilscontained in an internal combustion engine for lubricating purposes byoperating the internal combustion engine with a fuel containing aneffective amount of at least one of the said polyalkylene glycol hasbeen found.

It can be assumed that a part of the polyalkylene glycol mentionedcontained in the fuel is transported via the combustion chamber wherethe additive containing fuel is burnt into the lubricant oils and actingthere as a further lubricating agent. The advantage of this mechanism isthat the said further lubricating agent is continuously refreshed by thefuel feeding.

Spark-ignition internal combustion engines are preferably understood tomean gasoline engines, which are typically ignited with spark plugs. Inaddition to the customary four- and two-stroke gasoline engines,spark-ignition internal combustion engines also include other enginetypes, for example the Wankel engine. These are generally engines whichare operated with conventional gasoline types, especially gasoline typesaccording to EN 228, gasoline-alcohol mixtures such as Flex fuel with 75to 85% by volume of ethanol, liquid pressure gas (“LPG”) or compressednatural gas (“CNG”) as fuel.

However, the inventive use of the polyalkylene glycol mentioned alsorelates to newly developed internal combustion engines such as the“HCCI” engine, which is self-igniting and is operated with gasolinefuel.

The instant invention works preferably with direct injection gasolinedriven combustion engines.

Variable A in general formula I comprises C₃- to C₂₀-alkylene groups,which are normally derived from the corresponding hydrocarbyl epoxids,i.e. the corresponding alkylene oxides which are usually vicinalalkylene oxides such as 1,2-alkylene oxides. Examples for such alkyleneoxides are 1,2-pro-pylene oxide, 1,2-butylene oxide, 2,3-butylene oxide,2-methyl-1,2-propylene oxide, 1,2-pentylene oxide, 1,2-hexylene oxide,1,2-octylene oxide, 1,2-nonylene oxide, 1,2-decylene oxide,1,2-undecylene oxide, 1,2-dodecylene oxide, 1,2-tetradecylene oxide,1,2-hexadecylene oxide, 1,2-octadecylene oxide and 1,2-eicosylene oxide.Variable A may alternatively be definded for the above examples byformula —CHR⁴—CHR⁵— wherein R⁴ and R⁵ may independently be hydrogen or aC₁- to C₁₈ alkyl radical with at least one of R⁴ and R⁵ being a C₁- toC₁₈ alkyl radical and the sum of carbon atoms in R⁴ and R⁵ not exceedingthe number of 20.

Variable A in general formula I may be one single species of alkylenegroups or a mixture of different species of alkylene groups. Suchmixture may comprise three, four or preferably two different species ofalkylene groups. In case of one single species of alkylene groups, thepolyalkylene glycol mentioned is a block copolymer of two or, if the twovariables A at the two different sides of the —(CH₂CH₂—O)_(m)-block aredifferent, of three blocks. In case of one single species of alkylenegroups, variable A normally comprises of from 8 to 20 carbon atoms. Incase of a mixture of two or of more different species of alkylenegroups, the said outward-positioned moieties HO—(A—O)_(p)- and/or—(A—O)_(q)-H may be arranged randomly or blockwise.

In a preferred embodiment, variable A in general formula I is a mixtureof two different types of alkylene groups A¹ and A² with A¹ designatingone or more C₃- to C₇-alkylene groups and A² designating one or more C₈-to C₂₀-alkylene groups, A¹ and A² being arranged randomly or blockwise.A¹ designates preferably one or more C₃- to C₆-alkylene groups, morepreferably one or more C₃- to C₅-alkylene groups, most preferably C₃-and/or C₄-alkylene groups. A² designates preferably one or more C₈- toC₁₆-alkylene groups, more preferably one or more C₈- to C₁₄-alkylenegroups, most preferably one or more C₈- to C₁₂-alkylene groups.

In another preferred embodiment, variable A in general formula I is aC₈- to C₂₀-alkylene group (A²) or a mixture of C₈- to C₂₀-alkylenegroups (A²) arranged randomly.

The number m of —(CH₂CH₂—O)— units in the middle of the polyalkyleneglycol molecule is preferably from 2 to 50 or preferably from 3 to 75 orpreferably from 4 to 100, more preferably from 3 to 30, and mostpreferably from 4 to 15.

The numbers p and q, respectively, of outward-positioned moieties—(A—O)-units are preferably each from 2 to 50, more preferably each from3 to 35, and most preferably each from 4 to 20.

The numbers m, p and q are mean values as a statistical number, due to adistribution of alkoxylation homologues in the product.

The polyalkylene glycols mentioned are preferably obtainable byalkoxylation of polyethylene glycols of general formula II

HO—(CH₂CH₂—O)m—H  (II)

wherein m is a number of from 2 to 100,

-   -   with 2 to 200 moles of a C₃- to C₂₀-alkylene oxide or a mixture        of such alkylene oxides per mole of polyethylene glycol II, the        alkoxylation product being arranged randomly or blockwise.        Conditions for such alkylation reactions are well known and,        therefore, do not need to be described here. Polyethylene        glycols of general formula II of different chain lengths are        available from BASF SE (among others) under the trade name of        Pluriol® E.

Typical examples of polyalkylene glycols mentioned are polyethyleneglycols of general formula II with m=4 to 15 which are alkoxylated withone or simultaneously more C₈- to C₁₂-alkylene oxides (A²) resulting inrandom structures, or which are first alkoxylated with one or more C₈-to C₁₂-alkylene oxides (A²) and subsequently alkoxylated with one ormore C₃- and/or C₄-alkylene oxides (A¹) resulting in block structuresregarding A¹ and A².

The polyalkylene glycol mentioned is oil soluble, which means that, whenmixed with mineral oils and/or fuels in a weight ratio of 10:90, 50:50and 90:10, the polyalkylene glycol does not show phase separation afterstanding for 24 hours at room temperature for at least two weightrations out of the three weight ratios 10:90, 50:50 and 90:10.

The present invention also provides a fuel composition which comprises,in a major amount, a gasoline fuel and, in a minor amount, at least onepolyalkylene glycol mentioned, and at least one fuel additive which isdifferent from the said polyalkylene glycols and has detergent action.

Typically, the amount of this at least one polyalkylene glycol in thegasoline fuel is 10 to 5000 ppm by weight, more preferably 20 to 2000ppm by weight, even more preferably 30 to 1000 ppm by weight andespecially 40 to 500 ppm by weight, for example 50 to 300 ppm by weight.

Useful gasoline fuels include all conventional gasoline fuelcompositions. A typical representative which shall be mentioned here isthe Eurosuper base fuel to EN 228, which is customary on the market. Inaddition, gasoline fuel compositions of the specification according toWO 00/47698 are also possible fields of use for the present invention.In addition, in the context of the present invention, gasoline fuelsshall also be understood to mean alcohol-containing gasoline fuels,especially ethanol-containing gasoline fuels, as described, for example,in WO 2004/090079, for example Flex fuel with an ethanol content of 75to 85% by volume, or gasoline fuel comprising 85% by volume of ethanol(“E85”), but also the “E100” fuel type, which is typicallyazeotropically distilled ethanol and thus consists of approx. 96% byvolume of C₂H₅OH and approx. 4% by volume of H₂O.

The polyalkylene glycol mentioned may be added to the particular basefuel either alone or in the form of fuel additive packages (for gasolinefuels also called “gasoline performance packages). Such packages arefuel additive concentrates and generally also comprise, as well assolvents, and as well as the at least one fuel additive which isdifferent from the said polyalkylene glycols and has detergent action, aseries of further components as coadditives, which are especiallycarrier oils, corrosion inhibitors, demulsifiers, dehazers, antifoams,combustion improvers, antioxidants or stabilizers, antistats,metallocenes, metal deactivators, solubilizers, markers and/or dyes.

Detergents or detergent additives as the at least one fuel additivewhich is different from the said polyalkylene glycols and has detergentaction, referred to hereinafter as component (D), typically refer todeposition inhibitors for fuels. The detergent additives are preferablyamphiphilic substances which possess at least one hydrophobichydrocarbyl radical having a number-average molecular weight (M_(n)) of85 to 20 000, especially of 300 to 5000, in particular of 500 to 2500,and at least one polar moiety.

In a preferred embodiment, the inventive fuel composition comprises, asthe at least one fuel additive (D) which is different from the saidpolyalkylene glycols and has detergent action, at least onerepresentative which is selected from:

-   -   (Da) mono- or polyamino groups having up to 6 nitrogen atoms, at        least one nitrogen atom having basic properties;    -   (Db) nitro groups, optionally in combination with hydroxyl        groups;    -   (Dc) hydroxyl groups in combination with mono- or polyamino        groups, at least one nitrogen atom having basic properties;    -   (Dd) carboxyl groups or their alkali metal or alkaline earth        metal salts;    -   (De) sulfo groups or their alkali metal or alkaline earth metal        salts;    -   (Df) polyoxy-C₂-C₄-alkylene moieties terminated by hydroxyl        groups, mono- or polyamino groups, at least one nitrogen atom        having basic properties, or by carbamate groups;    -   (Dg) carboxylic ester groups;    -   (Dh) moieties derived from succinic anhydride and having        hydroxyl and/or amino and/or amido and/or imido groups; and/or    -   (Di) moieties obtained by Mannich reaction of substituted        phenols with aldehydes and mono- or polyamines.

The hydrophobic hydrocarbon radical in the above detergent additives,which ensures the adequate solubility in the fuel composition, has anumber-average molecular weight (M_(n)) of 85 to 20 000, especially of300 to 5000, in particular of 500 to 2500. Useful typical hydrophobichydrocarbyl radicals, especially in conjunction with the polar moieties(Da), (Dc), (Dh) and (Di), are relatively long-chain alkyl or alkenylgroups, especially the polypropenyl, polybutenyl and polyisobutenylradicals each having M_(n)=300 to 5000, especially 500 to 2500, inparticular 700 to 2300.

Examples of the above groups of detergent additives include thefollowing:

-   -   Additives comprising mono- or polyamino groups (Da) are        preferably polyalkenemono- or polyalkenepolyamines based on        polypropene or on highly-reactive (i.e. having predominantly        terminal double bonds in the α- and/or β-position such as        vinylidene double bonds) or conventional (i.e. having        predominantly internal double bonds) polybutene or polyisobutene        having M_(n)=300 to 5000. Such detergent additives based on        highly-reactive polybutene or polyisobutene, which are normally        prepared by hydroformylation of the poly(iso)butene and        subsequent reductive amination with ammonia, monoamines or        polyamines, are known from EP-A 244 616. When the preparation of        the additives proceeds from polybutene or polyisobutene having        predominantly internal double bonds (usually in the β- and/or γ-        positions), one possible preparative route is by chlorination        and subsequent amination or by oxidation of the double bond with        air or ozone to give the carbonyl or carboxyl compound and        subsequent amination under reductive (hydrogenating) conditions.        The amines used here for the amination may be, for example,        ammonia, monoamines or polyamines such as        dimethylaminopropylamine, ethylenediamine, diethylenetriamine,        triethylenetetramine or tetraethylenepentamine. Corresponding        additives based on polypropene are described in particular in        WO-A-94/24231.

Further preferred additives comprising monoamino groups (Da) are thehydrogenation products of the reaction products of polyisobutenes havingan average degree of polymerization P=5 to 100 with nitrogen oxides ormixtures of nitrogen oxides and oxygen, as described in particular inWO-A-97/03946.

Further preferred additives comprising monoamino groups (Da) are thecompounds obtainable from polyisobutene epoxides by reaction with aminesand subsequent dehydration and reduction of the amino alcohols, asdescribed in particular in DE-A-196 20 262.

Additives comprising nitro groups (Db), optionally in combination withhydroxyl groups, are preferably reaction products of polyisobuteneshaving an average degree of polymerization P=5 to 100 or 10 to 100 withnitrogen oxides or mixtures of nitrogen oxides and oxygen, as describedin particular in WO-A-96/03367 and in WO-A 96/03479. These reactionproducts are generally mixtures of pure nitropolyisobutenes (e.g.α,β-dinitropolyisobutene) and mixed hydroxynitropolyisobutenes (e.g.α-nitro-β-hydroxypolyisobutene).

Additives comprising hydroxyl groups in combination with mono- orpolyamino groups (Dc) are in particular reaction products ofpolyisobutene epoxides obtainable from polyisobutene having preferablypredominantly terminal double bonds and M_(n)=300 to 5000, with ammoniaor mono- or polyamines, as described in particular in EP-A-476 485.

Additives comprising carboxyl groups or their alkali metal or alkalineearth metal salts (Dd) are preferably copolymers of C₂-C₄₀-olefins withmaleic anhydride which have a total molar mass of 500 to 20 000 and someor all of whose carboxyl groups have been converted to the alkali metalor alkaline earth metal salts and any remainder of the carboxyl groupshas been reacted with alcohols or amines. Such additives are disclosedin particular by EP-A-307 815. Such additives serve mainly to preventvalve seat wear and can, as described in WO-A-87/01126, advantageouslybe used in combination with customary fuel detergents such aspoly(iso)buteneamines or polyetheramines.

Additives comprising sulfo groups or their alkali metal or alkalineearth metal salts (De) are preferably alkali metal or alkaline earthmetal salts of an alkyl sulfosuccinate, as described in particular inEP-A-639 632. Such additives serve mainly to prevent valve seat wear andcan be used advantageously in combination with customary fuel detergentssuch as poly(iso)buteneamines or polyetheramines.

Additives comprising polyoxy-C₂-C₄-alkylene moieties (Df) are preferablypolyethers or polyetheramines which are obtainable by reaction ofC₂-C₆₀-alkanols, C₆-C₃₀-alkane-diols, mono- or di-C₂-C₃₀-alkylamines,C₁-C₃₀-alkylcyclohexanols or C₁-C₃₀-alkylphenols with 1 to 30 mol ofethylene oxide and/or propylene oxide and/or butylene oxide per hydroxylgroup or amino group and, in the case of the polyetheramines, bysubsequent reductive amination with ammonia, monoamines or polyamines.Such products are described in particular in EP-A-310 875, EP-A-356 725,EP-A-700 985 and U.S. Pat. No. 4,877,416. In the case of polyethers,such products also have carrier oil properties. Typical examples ofthese are tridecanol butoxylates, isotridecanol butoxylates,isononyl-phenol butoxylates and polyisobutenol butoxylates andpropoxylates and also the corresponding reaction products with ammonia.

Additives comprising carboxylic ester groups (Dg) are preferably estersof mono-, di- or tricarboxylic acids with long-chain alkanols orpolyols, in particular those having a minimum viscosity of 2 mm²/s at100° C., as described in particular in DE-A-38 38 918. The mono-, di- ortricarboxylic acids used may be aliphatic or aromatic acids, andparticularly suitable ester alcohols or ester polyols are long-chainrepresentatives having, for example, 6 to 24 carbon atoms. Typicalrepresentatives of the esters are adipates, phthalates, isophthalates,terephthalates and trimellitates of isooctanol, of isononanol, ofisodecanol and of isotridecanol. Such products also have carrier oilproperties.

Additives comprising moieties derived from succinic anhydride and havinghydroxyl and/or amino and/or amido and/or imido groups (Dh) arepreferably corresponding derivatives of alkyl- or alkenyl-substitutedsuccinic anhydride and especially the corresponding derivatives ofpolyisobutenylsuccinic anhydride which are obtainable by reactingconventional or high-reactivity polyisobutene having M_(n)=300 to 5000with maleic anhydride by a thermal route or via the chlorinatedpolyisobutene. Of particular interest in this context are derivativeswith aliphatic polyamines such as ethylenediamine, diethylenetriamine,triethylenetetramine or tetraethylenepentamine. The moieties havinghydroxyl and/or amino and/or amido and/or imido groups are, for example,carboxylic acid groups, acid amides of monoamines, acid amides of di- orpolyamines which, in addition to the amide function, also have freeamine groups, succinic acid derivatives having an acid and an amidefunction, carboximides with monoamines, carboximides with di- orpolyamines which, in addition to the imide function, also have freeamine groups, or diimides which are formed by the reaction of di- orpolyamines with two succinic acid derivatives. Such fuel additives aredescribed especially in U.S. Pat. No. 4,849,572.

The detergent additives from group (Dh) are preferably the reactionproducts of alkyl- or alkenyl-substituted succinic anhydrides,especially of polyisobutenylsuccinic anhydrides (“PIBSAs”), with aminesand/or alcohols. These are thus derivatives which are derived fromalkyl-, alkenyl- or polyisobutenylsuccinic anhydride and have aminoand/or amido and/or imido and/or hydroxyl groups. It is self-evidentthat these reaction products are obtainable not only when substitutedsuccinic anhydride is used, but also when substituted succinic acid orsuitable acid derivatives, such as succinyl halides or succinic esters,are used.

The additized fuel may comprise at least one detergent based on apolyisobutenyl-substituted succinimide. Especially of interest are theimides with aliphatic polyamines. Particularly preferred polyamines areethylenediamine, diethylenetriamine, triethylenetetramine,pentaethylenehexamine and in particular tetraethylenepentamine. Thepolyisobutenyl radical has a number-average molecular weight M_(n) ofpreferably from 500 to 5000, more preferably from 500 to 2000 and inparticular of about 1000.

Additives comprising moieties (Di) obtained by Mannich reaction ofsubstituted phenols with aldehydes and mono- or polyamines arepreferably reaction products of polyisobutene-substituted phenols withformaldehyde and mono- or polyamines such as ethylenediamine,di-ethylenetriamine, triethylenetetramine, tetraethylenepentamine ordimethylaminopropylamine. The polyisobutenyl-substituted phenols mayoriginate from conventional or high-reactivity polyisobutene havingM_(n)=300 to 5000. Such “polyisobutene Mannich bases” are describedespecially in EP-A-831 141.

The inventive fuel composition comprises the at least one fuel additivewhich is different from the polyalkylene glycols mentioned and hasdetergent action, and is normally selected from the above groups (Da) to(Di), in an amount of typically 10 to 5000 ppm by weight, morepreferably of 20 to 2000 ppm by weight, even more preferably of 30 to1000 ppm by weight and especially of 40 to 500 ppm by weight, forexample of 50 to 250 ppm by weight.

The detergent additives (D) mentioned are preferably used in combinationwith at least one carrier oil. In a preferred embodiment, the inventivefuel composition comprises, in addition to the at least one polyalkyleneglycol mentioned and the at least one fuel additive which is differentthan the polyalkylene glycol mentioned and has detergent action, as afurther fuel additive in a minor amount, at least one carrier oil.

Suitable mineral carrier oils are the fractions obtained in crude oilprocessing, such as brightstock or base oils having viscosities, forexample, from the SN 500-2000 class; but also aromatic hydrocarbons,paraffinic hydrocarbons and alkoxyalkanols. Likewise useful is afraction which is obtained in the refining of mineral oil and is knownas “hydrocrack oil” (vacuum distillate cut having a boiling range offrom about 360 to 500° C., obtainable from natural mineral oil which hasbeen catalytically hydrogenated under high pressure and isomerized andalso deparaffinized). Likewise suitable are mixtures of abovementionedmineral carrier oils.

Examples of suitable synthetic carrier oils are selected from:polyolefins (poly-alpha-olefins or poly(internal olefin)s),(poly)esters, (poly)alkoxylates, polyethers, aliphatic polyetheramines,alkylphenol-started polyethers, alkylphenol-started polyetheramines andcarboxylic esters of long-chain alkanols. For the avoidance of doubt,the said (poly)alkoxylates and polyethers which are suitable assynthetic carrier oils for the instant invention, are different from thepolyalkylene glycols mentioned.

Examples of suitable polyolefins are olefin polymers having M_(n)=from400 to 1800, in particular based on polybutene or polyisobutene(hydrogenated or unhydrogenated).

Examples of suitable polyethers or polyetheramines are preferablycompounds comprising polyoxy-C₂-C₄-alkylene moieties which areobtainable by reacting C₂-C₆₀-alkanols, C₆-C₃₀-alkanediols, mono- ordi-C₂-C₃₀-alkylamines, C₁-C₃₀-alkylcyclohexanols or C₁-C₃₀-alkylphenolswith from 1 to 30 mol of ethylene oxide and/or propylene oxide and/orbutylene oxide per hydroxyl group or amino group, and, in the case ofthe polyetheramines, by subsequent reductive amination with ammonia,monoamines or polyamines. Such products are described in particular inEP-A-310 875, EP-A-356 725, EP-A-700 985 and U.S. Pat. No. 4,877,416.For example, the polyether-amines used may be poly-C₂-C₆-alkylene oxideamines or functional derivatives thereof. Typical examples thereof aretridecanol butoxylates or isotridecanol butoxylates, isononylphenolbutoxylates and also polyisobutenol butoxylates and propoxylates, andalso the corresponding reaction products with ammonia.

Examples of carboxylic esters of long-chain alkanols are in particularesters of mono-, di- or tricarboxylic acids with long-chain alkanols orpolyols, as described in particular in DE-A-38 38 918. The mono-, di- ortricarboxylic acids used may be aliphatic or aromatic acids; suitableester alcohols or polyols are in particular long-chain representativeshaving, for example, from 6 to 24 carbon atoms. Typical representativesof the esters are adipates, phthalates, isophthalates, terephthalatesand trimellitates of isooctanol, isononanol, isodecanol andisotridecanol, for example di(n- or isotridecyl) phthalate.

Further suitable carrier oil systems are described, for example, inDE-A-38 26 608, DE-A-41 42 241, DE-A-43 09 074, EP-A-0 452 328 andEP-A-0 548 617.

Examples of particularly suitable synthetic carrier oils arealcohol-started polyethers having from about 5 to 35, for example fromabout 5 to 30, C₃-C₆-alkylene oxide units, for example selected frompropylene oxide, n-butylene oxide and isobutylene oxide units, ormixtures thereof. Nonlimiting examples of suitable starter alcohols arelong-chain alkanols or phenols substituted by long-chain alkyl in whichthe long-chain alkyl radical is in particular a straight-chain orbranched C₆-C₁₈-alkyl radical. Preferred examples include tridecanol andnonylphenol.

Further suitable synthetic carrier oils are alkoxylated alkylphenols, asdescribed in DE-A-101 02 913.

Preferred carrier oils are synthetic carrier oils, particular preferencebeing given to poly-ethers.

When a carrier oil is used in addition, it is added to the inventiveadditized fuel in an amount of preferably from 1 to 1000 ppm by weight,more preferably from 10 to 500 ppm by weight and in particular from 20to 100 ppm by weight.

In a preferred embodiment, the inventive fuel composition comprises, inaddition to the at least one polyalkylene glycol mentioned, the at leastone fuel additive which is different from the polylalkylene glycolmentioned and has detergent action, and optionally the at least onecarrier oil, as a further fuel additive in a minor amount at least onetertiary hydrocarbyl amine of formula NR¹R²R³ wherein R¹, R² and R³ arethe same or different C₁- to C₂₀-hydrocarbyl residues with the provisothat the overall number of carbon atoms in formula NR¹R²R³ does notexceed 30.

Tertiary hydrocarbyl amines have proven to be advantageous with regardto use as performance additives in fuels controlling deposits. Besidestheir superior performance behavior, they are also good to handle astheir melting points are normally low enough to be usually liquid atambient temperature.

“Hydrocarbyl residue” for R¹ to R³ shall mean a residue which isessentially composed of carbon and hydrogen, however, it can contain insmall amounts heteroatomes, especially oxygen and/or nitrogen, and/orfunctional groups, e.g. hydroxyl groups and/or carboxylic groups, to anextent which does not distort the predominantly hydrocarbon character ofthe residue. Hydrocarbyl residues are preferably alkyl, alkenyl,alkinyl, cycloalkyl, aryl, alkylaryl or arylalkyl groups. Especiallypreferred hydrocarbyl residues for R¹ to R³ are linear or branched alkylor alkenyl groups.

The overall number of carbon atoms in the tertiary hydrocarbyl aminementioned is at most 30, preferably at most 27, more preferably at most24, most preferably at most 20. Preferably, the minimum overall numberof carbon atoms in formula NR¹R²R³ is 6, more preferably 8, mostpreferably 10. Such size of the tertiary hydrocarbyl amine mentionedcorresponds to molecular weight of about 100 to about 450 for thelargest range and of about 150 to about 300 for the smallest range; mostusually, tertiary hydrocarbyl amines mentioned within a molecular rangeof from 100 to 300 are used.

The three C₁- to C₂₀-hydrocarbyl residues may be identical or different.Preferably, they are different, thus creating an amine molecular whichexhibits an oleophobic moiety (i.e. the more polar amino group) and anoleophilic moiety (i.e. a hydrocarbyl residue with a longer chain lengthor a larger volume). Such amine molecules with oleophobic/oleophilicbalance have proved to show the best deposit control performanceaccording the present invention.

Preferably, a tertiary hydrocarbyl amine of formula NR¹R²R³ is usedwherein at least two of hydrocarbyl residues R¹, R² and R³ are differentwith the proviso that the hydrocarbyl residue with the most carbon atomsdiffer in carbon atom number from the hydrocarbyl residue with thesecond most carbon atoms in at least 3, preferably in at least 4, morepreferably in at least 6, most preferably in at least 8. Thus, thetertiary amines mentioned exhibit hydrocarbyl residues of two or threedifferent chain length or different volume, respectively.

Still more preferably, a tertiary hydrocarbyl amine of formula NR¹R²R³is used wherein one or two of R¹ to R³ are C₇- to C₂₀-hydrocarbylresidues and the remaining two or one of R¹ to R³ are C₁- toC₄-hydrocarbyl residues.

The one or the two longer hydrocarbyl residues, which may be in case oftwo residues identical or different, exhibit from 7 to 20, preferablyfrom 8 to 18, more preferably from 9 to 16, most preferably from 10 to14 carbon atoms. The one or the two remaining shorter hydrocarbylresidues, which may be in case of two residues identical or different,exhibit from 1 to 4, preferably from 1 to 3, more preferably 1 or 2,most preferably 1 carbon atom(s). Besides the desired depositcontrolling performance, the oleophilic long-chain hydrocarbyl residuesprovide further advantageous properties to the tertiary amines, i.e.high solubility for gasoline fuels and low volatility.

More preferably, tertiary hydrocarbyl amines of formula NR¹R²R³ areused, wherein R¹ is a C₈- to C₁₈-hydrocarbyl residue and R² and R³ areindependently of each other C₁- to C₄-alkyl radicals. Still morepreferably, tertiary hydrocarbyl amines of formula NR¹R²R³ are used,wherein R¹ is a C₉- to C₁₆-hydrocarbyl residue and R² and R³ are bothmethyl radicals.

Examples for suitable linear or branched C₁- to C₂₀-alkyl residues forR¹ to R³ are: methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl,sec.-butyl, tert-butyl, n-pentyl, tert-pentyl, 2-methylbutyl,3-methylbutyl,1,1-dimethylpropyl,1,2-dimethylpropyl, n-hexyl,2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl,1,2-dimethylbutyl, 1,3-dimethylbutyl, 2-ethylbutyl, n-heptyl,1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl,5-methylhexyl, 1,1-dimethylpentyl, 1,2-dimethylpentyl,2,2-dimethylpentyl, 2,3-dimethylpentyl, 2,4-dime-thylpentyl,2,5-dimethylpentyl, 2-diethylpentyl, 3-diethyl-pentyl, n-octyl,1-methylheptyl, 2-methylheptyl, 3-methylheptyl, 4-methylheptyl,5-methylheptyl, 6-methylheptyl, 1,1-dimethylhexyl, 1,2-dimethylhexyl,2,2-dimethylhexyl, 2,3-dimethylhexyl, 2,4-dimethyl-hexyl,2,5-dimethylhexyl, 2,6-dimethylhexyl, 2-ethyl-hexyl, 3-ethylhexyl,4-ethylhexyl, n-nonyl, iso-nonyl, n-decyl, 1-propylheptyl,2-propyl-heptyl, 3-propylheptyl, n-undecyl, n-dodecyl, n-tridecyl,iso-tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,nonadecyl and eicosyl.

Examples for suitable linear or branched C₂- to C₂₀-alkenyl and -alkinylresidues for R¹ to R³ are: vinyl, allyl, oleyl and propin-2-yl.

Tertiary hydrocarbyl amines of formula NR¹R²R³ with long-chain alkyl andalkenyl residues can also preferably be obtained or derived from naturalsources, i.e. from plant or animal oils and lards. The fatty aminesderived from such sources which are suitable as such tertiaryhydrocarbyl amines normally form mixtures of differents similar speciessuch as homologues, e.g. tallow amines containing as main componentstetradecyl amine, hexadecyl amine, octadecyl amine and octadecenyl amine(oleyl amine). Further examples of suitable fatty amines are: cocoamines and palm amines. Unsaturated fatty amines which contain alkenylresidues can be hydrogenated and used in this saturated form.

Examples for suitable C₃- to C₂₀-cycloalkyl residues for R¹ to R³ are:cyclopropyl, cyclobutyl, 2-methylcyclohexyl, 3-methylcyclohexyl,4-methylcyclohexyl, 2,3-dimethyl-cyclohexyl, 2,4-dimethylcyclohexyl,2,5-dimethylcyclohexyl, 2,6-dimethylcyclohexyl, 3,4-dimethylcyclohexyl,3,5-dimethylcyclohexyl, 2-ethylcyclohexyl, 3-ethylcyclohexyl,4-ethylcyclohexyl, cyclooctyl and cyclodecyl.

Examples for suitable C₇- to C₂₀-aryl, -alkylaryl or -arylalkyl residuesfor R¹ to R³ are: naphthyl, tolyl, xylyl, n-octylphenyl, n-nonylphenyl,n-decylphenyl, benzyl, 1-phenyl-ethyl, 2-phenylethyl, 3-phenylpropyl and4-butylphenyl.

Typical examples for suitable tertiary hydrocarbyl amines of formulaNR¹R²R³ are the following:

-   -   N,N-dimethyl-n-butylamine, N,N-dimethyl-n-pentylamine,        N,N-dimethyl-n-hexylamine, N,N-dimethyl-n-heptylamine,        N,N-dimethyl-n-octylamine, N,N-dimethyl-2-ethylhexyl-amine,        N,N-di-methyl-n-nonylamine, N,N-dimethyl-iso-nonylamine,        N,N-dimethyl-n-decylamine, N,N-dimethyl-2-propylheptylamine,        N,N-dimethyl-n-undecylamine, N,N-dimethyl-n-dodecylamine,        N,N-dimethyl-n-tridecylamine, N,N-dimethyl-iso-tridecyl-amine,        N,N-dimethyl-n-tetradecylamine, N,N-dimethyl-n-hexadecylamine,        N,N-di-methyl-n-octadecylamine, N,N-dimethyl-eicosylamine,        N,N-dimethyl-oleylamine;    -   N,N-diethyl-n-heptylamine, N,N-diethyl-n-octylamine,        N,N-diethyl-2-ethylhexylamine, N,N-diethyl-n-nonylamine,        N,N-diethyl-iso-nonylamine, N,N-diethyl-n-decylamine,        N,N-diethyl-2-propylheptylamine, N,N-diethyl-n-undecylamine,        N,N-diethyl-n-dodecylamine, N,N-diethyl-n-tridecylamine,        N,N-diethyl-iso-tridecylamine, N,N-diethyl-n-tetradecyl-amine,        N,N-diethyl-n-hexadecylamine, N,N-di-ethyl-n-octadecylamine,        N,N-diethyl-eicosylamine, N,N-diethyl-oleylamine;    -   N,N-di-(n-propyl)-n-heptylamine, N,N-di-(n-propyl)-n-octylamine,        N,N-di-(n-propyl)-2-ethylhexylamine,        N,N-di-(n-propyl)n-nonylamine, N,N-di-(n-propyl)-iso-nonylamine,        N,N-di-(n-propyl)-n-decylamine,        N,N-di-(n-propyl)-2-propylheptylamine,        N,N-di-(n-propyl)n-undecylamine,    -   N,N-di-(n-propyl)-n-dodecylamine,        N,N-di-(n-propyl)-n-tri-decylamine,        N,N-di-(n-propyl)-iso-tridecylamine,        N,N-di-(n-propyl)-n-tetradecylamine,        N,N-di-(n-propyl)-n-hexadecylamine,        N,N-di-(n-propyl)-n-octadecylamine,        N,N-di-(n-propyl)-eicosylamine, N,N-di-(n-propyl)-oleylamine;    -   N,N-di-(n-butyl)-n-heptylamine, N,N-di-(n-butyl)-n-octylamine,        N,N-di-(n-butyl)-2-ethyl-hexylamine,        N,N-di-(n-butyl)-n-nonylamine, N,N-di-(n-butyl)-iso-nonylamine,        N,N-di-(n-butyl)-n-decylamine,        N,N-di-(n-butyl)-2-propylheptylamine,        N,N-di-(n-butyl)-n-undecyl-amine,        N,N-di-(n-butyl)-n-dodecylamine,        N,N-di-(n-butyl)-n-tridecylamine,        N,N-di-(n-butyl)-iso-tridecylamine,        N,N-di-(n-butyl)-n-tetradecylamine,        N,N-di-(n-butyl)-n-hexa-decylamine,        N,N-di-(n-butyl)-n-octadecylamine,        N,N-di-(n-butyl)-eicosylamine, N,N-di-(n-butyl)-oleyl-amine;    -   N-methyl-N-ethyl-n-heptylamine, N-methyl-N-ethyl-n-octylamine,        N-methyl-N-ethyl-2-ethylhexylamine,        N-methyl-N-ethyl-n-nonylamine, N-methyl-N-ethyl-iso-nonylamine,        N-methyl-N-ethyl-n-decylamine,        N-methyl-N-ethyl-2-propylheptylamine,        N-methyl-N-ethyl-n-undecylamine,        N-methyl-N-ethyl-n-dodecylamine,        N-methyl-N-ethyl-n-tridecylamine,        N-methyl-N-ethyl-iso-tridecylamine,        N-methyl-N-ethyl-n-tetradecylamine,        N-methyl-N-ethyl-n-hexadecylamine,        N-methyl-N-ethyl-n-octadecylamine,        N-methyl-N-ethyl-eicosyl-amine, N-methyl-N-ethyl-oleylamine;    -   N-methyl-N-(n-propyl)-n-heptylamine,        N-methyl-N-(n-propyl)-n-octylamine,        N-methyl-N-(n-propyl)-2-ethylhexylamine,        N-methyl-N-(n-propyl)-n-nonylamine,        N-methyl-N-(n-propyl)-iso-nonylamine,        N-methyl-N-(n-propyl)-n-decylamine,        N-methyl-N-(n-propyl)-2-propylheptylamine,        N-methyl-N-(n-propyl)-n-undecylamine,        N-methyl-N-(n-propyl)-n-dodecylamine,        N-methyl-N-(n-propyl)-n-tridecylamine,        N-methyl-N-(n-propyl)-iso-tri-decylamine,        N-methyl-N-(n-propyl)-n-tetradecylamine,        N-methyl-N-(n-propyl)-n-hexa-decylamine,        N-methyl-N-(n-propyl)-n-octadecylamine,        N-methyl-N-(n-propyl)-eicosyl-amine,        N-methyl-N-(n-propyl)-oleylamine;    -   N-methyl-N-(n-butyl)-n-heptylamine,        N-methyl-N-(n-butyl)-n-octylamine,        N-methyl-N-(n-butyl)-2-ethylhexylamine,        N-methyl-N-(n-butyl)-n-nonylamine,        N-methyl-N-(n-butyl)-iso-nonylamine,        N-methyl-N-(n-butyl)-n-decylamine,        N-methyl-N-(n-butyl)-2-propylheptyl-amine,        N-methyl-N-(n-butyl)-n-undecylamine,        N-methyl-N-(n-butyl)-n-dodecylamine,        N-methyl-N-(n-butyl)-n-tridecylamine,        N-methyl-N-(n-butyl)-iso-tridecylamine,        N-methyl-N-(n-butyl)-n-tetradecylamine,        N-methyl-N-(n-butyl)-n-hexadecylamine,        N-methyl-N-(n-butyl)-n-octadecylamine,        N-methyl-N-(n-butyl)-eicosylamine,        N-methyl-N-(n-butyl)-oleylamine;    -   N-methyl-N,N-di-(n-heptyl)-amine,        N-methyl-N,N-di-(n-octyl)-amine,        N-methyl-N,N-di-(2-ethylhexyl)-amine,        N-methyl-N,N-di-(n-nonyl)-amine,        N-methyl-N,N-di-(iso-nonyl)-amine,        N-methyl-N,N-di-(n-decyl)-amine,        N-methyl-N,N-di-(2-propylheptyl)-amine,        N-methyl-N,N-di-(n-undecyl)-amine,        N-methyl-N,N-di-(n-dodecyl)-amine,        N-methyl-N,N-di-(n-tridecyl)-amine,        N-methyl-N,N-di-(iso-tridecyl)-amine,        N-methyl-N,N-di-(n-tetra-decyl)-amine;    -   N-ethyl-N,N-di-(n-heptyl)-amine, N-ethyl-N,N-di-(n-octyl)-amine,        N-ethyl-N,N-di-(2-ethylhexyl)-amine,        N-ethyl-N,N-di-(n-nonyl)-amine,        N-ethyl-N,N-di-(iso-nonyl)-amine,        N-ethyl-N,N-di-(n-decyl)-amine,        N-ethyl-N,N-di-(2-propylheptyl)-amine,        N-ethyl-N,N-di-(n-undecyl)-amine,        N-ethyl-N,N-di-(n-dodecyl)-amine,        N-ethyl-N,N-di-(n-tridecyl)-amine,        N-ethyl-N,N-di-(iso-tridecyl)-amine,        N-ethyl-N,N-di-(n-tetradecyl)-amine;    -   N-(n-butyl)-N,N-di-(n-heptyl)-amine,        N-(n-butyl)-N,N-di-(n-octyl)-amine,        N-(n-butyl)-N,N-di-(2-ethylhexyl)-amine,        N-(n-butyl)-N,N-di-(n-nonyl)-amine,        N-(n-butyl)-N,N-di-(iso-nonyl)-amine,        N-(n-butyl)-N,N-di-(n-decyl)-amine,        N-(n-butyl)-N,N-di-(2-propylheptyl)-amine,        N-(n-butyl)-N,N-di-(n-undecyl)-amine,        N-(n-butyl)-N,N-di-(n-dodecyl)-amine,        N-(n-butyl)-N,N-di-(n-tridecyl)-amine, N-(n-butyl)-N,        N-di-(iso-tridecyl)-amine;    -   N-methyl-N-(n-heptyl)-N-(n-dodecyl)-amine,        N-methyl-N-(n-heptyl)-N-(n-octadecyl)-amine,        N-methyl-N-(n-octyl)-N-(2-ethylhexyl)-amine,        N-methyl-N-(2-ethylhexyl)-N-(n-dodecyl)-amine,        N-methyl-N-(2-propylheptyl)-N-(n-undecyl)-amine,        N-methyl-N-(n-decyl)-N-(n-dodecyl)-amine,        N-methyl-N-(n-decyl)-N-(-tetradecyl)-amine,        N-methyl-N-(n-decyl)-N-(n-hexadecyl)-amine,        N-methyl-N-(n-decyl)-N-(n-octadecyl)-amine,        N-methyl-N-(n-decyl)-N-oleylamine,        N-methyl-N-(n-dodecyl)-N-(iso-tridecyl)-amine,        N-methyl-N-(n-dodecyl)-N-(n-tetradecyl)-amine,        N-methyl-N-(n-dodecyl)-N-(n-hexa-decyl)-amine,        N-methyl-N-(n-dodecyl)-oleylamine;

Also suitable tertiary hydrocarbyl amines of formula NR¹R²R³ aremonocyclic structures, wherein one of the short-chain hydrocarbylresidue forms with the nitrogen atom and with the other short-chainhydrocarbyl residue a five- or six-membered ring. Oxygen atoms and/orfurther nitrogen atoms may additionally be present in such five- orsix-membered ring. In each case, such cyclic tertiary amines carry atthe nitrogen atom or at one of the nitrogen atoms, respectively, thelong-chain C₇- to C₂₀-hydrocarbyl residue. Examples for such monocyclictertiary amines are N-(C₇- to C₂₀-hydrocarbyl)-piperidines, N-(C₇- toC₂₀-hydrocarbyl)piperazines and N-(C₇- to C₂₀-hydrocarbyl)-morpholines.

The inventive fuel composition may comprise further customarycoadditives, as described below:

Corrosion inhibitors suitable as such coadditives are, for example,succinic esters, in particular with polyols, fatty acid derivatives, forexample oleic esters, oligomerized fatty acids and substitutedethanolamines.

Demulsifiers suitable as further coadditives are, for example, thealkali metal and alkaline earth metal salts of alkyl-substituted phenol-and naphthalenesulfonates and the alkali metal and alkaline earth metalsalts of fatty acid, and also alcohol alkoxylates, e.g. alcoholethoxylates, phenol alkoxylates, e.g. tert-butylphenol ethoxylates ortert-pentylphenol ethoxylates, fatty acid, alkylphenols, condensationproducts of ethylene oxide and propylene oxide, e.g. ethyleneoxide-propylene oxide block copolymers, polyethyleneimines andpolysiloxanes. For the avoidance of doubt, the said condensationproducts of ethylene oxide and propylene oxide which are suitable asdemusifiers for the instant invention, are different from thepolyalkylene glycols mentioned.

Dehazers suitable as further coadditives are, for example, alkoxylatedphenol-formal-dehyde condensates.

Antifoams suitable as further coadditives are, for example,polyether-modified poly-siloxanes.

Antioxidants suitable as further coadditives are, for example,substituted phenols, e.g. 2,6-di-tert-butylphenol and2,6-di-tert-butyl-3-methylphenol, and also phenylenedi-amines, e.g.N,N′-di-sec-butyl-p-phenylenediamine.

Metal deactivators suitable as further coadditives are, for example,salicylic acid derivatives, e.g. N,N′-disalicylidene-1,2-propanediamine.

Suitable solvents, especially also for fuel additive packages, are, forexample, nonpolar organic solvents, especially aromatic and aliphatichydrocarbons, for example toluene, xylenes, “white spirit” and thetechnical solvent mixtures of the designations Shellsol® (manufacturer:Royal Dutch/Shell Group), Exxol® (manufacturer: ExxonMobil) and SolventNaphtha. Also useful here, especially in a blend with the nonpolarorganic solvents mentioned, are polar organic solvents, in particularalcohols such as tert-butanol, isoamyl alcohol, 2-ethylhexanol and2-propylheptanol.

When the coadditives and/or solvents mentioned are used in addition ingasoline fuel, they are used in the amounts customary therefor.

In an especially preferred embodiment, as the at least one fuel additive(D) to be used together with the polyalkylene glycol mentioned which isdifferent from the said polyalkylenen glycol and has detergent action isselected from (Da) polyisobutene monoamines or polyisobutene polyamineshaving Mn=300 to 5000, having predominantly vinylidene double bonds(normally at least 50 mol-% of vinylidene double bonds, especially atleast 70 mol-% of vinylidene double bonds) and having been prepared byhydroformylation of the respective polyisobutene and subsequentreductive amination with ammonia, monoamines or polyamines. Suchpolyisobutene monoamines and polyisobutene polyamines are preferablyapplied in combination with at least one mineral or synthetic carrieroil, more preferably in combination with at least one polyether-based orpolyetheramine-based carrier oil, most preferably in combination with atleast one C₆-C₁₈-alcohol-started polyether having from about 5 to 35C₃-C₆-alkylene oxide units, especially selected from propylene oxide,n-butylene oxide and isobutylene oxide units, as described above.

The present invention also provides an additive concentrate whichcomprises at least one polyalkylene glycol mentioned, and at least onefuel additive which is different from the said polyalkylene glycols andhas detergent action. Otherwise, the inventive additive concentrate maycomprise the further coadditives mentioned above. In case of additiveconcentrates for gasoline fuels, such additive concentrates are alsocalled gasoline performance packages.

The at least one polyalkylene glycol mentioned is present in theinventive additive concentrate preferably in an amount of 1 to 99% byweight, more preferably of 15 to 95% by weight and especially of 30 to90% by weight, based in each case on the total weight of theconcentrate. The at least one fuel additive which is different from thepolyalkylene glycols mentioned and has detergent action is present inthe inventive additive concentrate preferably in an amount of 1 to 99%by weight, more preferably of 5 to 85% by weight and especially of 10 to70% by weight, based in each case on the total weight of theconcentrate.

The polyalkylene glycol mentioned provides for quite a series ofadvantages and unexpected performance and handling improvements in viewof the respective solutions proposed in the art. Effective fuel savingin the operation of a spark-ignited internal combustion engine isachieved. The respective fuel additive concentrates remain homogeneouslystable over a prolonged period without any phase separation and/orprecipitates. Miscibility with other fuel additives is improved and thetendency to form emulsions with water is suppressed. The high level ofintake valve and combustion chamber cleanliness achieved by the modernfuel additives is not being worsened by the presence of the polyalkyleneglycol mentioned in the fuel, the level of intake valve and combustionchamber cleanliness is even in most cases increased. Power loss ininternal combustion engines is minimized and acceleration of internalcombustion engines is improved. The presence of the polyalkylene glycolmentioned in the fuel also provides for an improved lubricatingperformance of the lubricating oils in the internal combustion engine.

The examples which follow are intended to further illustrate the presentinvention without restricting it.

EXAMPLES Example 1: Preparation of a Polyalkylene Glycol “PAG 1”

Polyethylene glycol (m=about 4) available from BASF SE under the tradename of Pluriol® E 200 was dried and simultaneously reacted with 12moles of 1,2-dodecylene oxide per mole of polyethylene glycol and 20moles of 1,2-butylene oxide per mole of polyethylene oxide in thepresence of sodium methoxide as an alkoxylation catalyst at 130° C.,resulting in randomly arranged outward-positioned —(A—O)-units. Thepolyalkylene glycol obtained after purification proceedings by ionexchange resin, exhibited a kinematic viscosity of 27 mm²/s at 100° C.

Example 2: Preparation of a Polyalkylene Glycol “PAG 2”

Polyethylene glycol (m=about 9) available from BASF SE under the tradename of Pluriol® E 405 was dried and simultaneously reacted with 12moles of 1,2-dodecylene oxide per mole of polyethylene glycol and 20moles of 1,2-butylene oxide per mole of polyethylene oxide in thepresence of sodium methoxide as an alkoxylation catalyst at 130° C.,resulting in randomly arranged outward-positioned —(A—O)-units. Thepolyalkylene glycol obtained after purification proceedings by ionexchange resin, exhibited a kinematic viscosity of 27 mm²/s at 100° C.

Example 3: Storage Stability

48.0% by weight of a customary gasoline performance package (“GPP 1”)containing as detergent additive component Kerocom® PIBA (apolyisobutene monoamine made by BASF SE, based on a polyisobutene withM_(n)=1000) and usual polyether-based carrier oils, aliphatichydrocarbons as a diluent, demulsifiers and corrosion inhibitors incustomary amounts, 37.7% by weight of xylene and 14.3% by weight ofpolyalkylene glycol of Example 1 (“PAG 1”) above, were mixed at 20° C.and stored thereafter in a sealed glass bottle at −20° C. for 42 days.At the beginning of this storage period and then after each 7 days, themixture was evaluated visually and checked for possible phase separationand precipitation. It is the aim that the mixture remains clear (“c”),homogeneous (“h”) and liquid (“l”) after storage and does not exhibitany phase separation (“ps”) or precipitation (“pr”). The following tableshows the results of the evaluations:

after 7 days c, h, l after 14 days c, h, l after 21 days c, h, l after28 days c, h, l after 35 days c, h, l after 42 days c, h, l Result: pass

Example 4: Engine Cleanliness Tests

In order to demonstrate that the polyalkylene glycols mentioned do notdecrease engine cleanliness and that engine cleanliness is in most caseseven increased by the polyalkylene glycols mentioned, the average IVDvalues and the TCD values were determined with 250 mg/kg of the samegasoline performance package (“GPP 1”) as used in Example 3 abovecontaining additionally 150 mg/kg of polyalkylene glycol “PAG 1”, and,for comparison, with 250 mg/kg of the same gasoline performance packagewithout “PAG 1” (referred to as “GPP 2”), according to CEC F-20-98 witha Mercedes Benz M111 E engine using a customary RON 95 E10 gasoline fueland a customary RL-223/5 engine oil. The following table shows theresults of the deter-minations:

Additive average IVD [mg/valve] TCD [mg] GPP 1 3.25 4639 GPP 2 13.255109

1. A method for improving performance of an internal combustion engine,the method comprising: adding an fuel additive to fuel of the internalcombustion engine, wherein the fuel additive comprises a polyalkyleneglycol of formula IHO—(A—O)_(p)—(CH₂CH₂—O)_(m)—(A—O)_(q)—H  (I), wherein A is a C₃- toC₂₀-alkylene group or a mixture thereof, m is a number of from 2 to 100,p and q are each numbers of from 1 to 100, and said improving isselected from the group consisting of: reducing fuel consumption,minimizing power loss and improving acceleration of the internalcombustion engine, and improving lubricity of lubricant oils containedin the internal combustion engine.
 2. The method of claim 1, whereinsaid improving is minimizing power loss in the internal combustionengine and improving acceleration of the internal combustion engine. 3.The method of claim 1, wherein said improving is improving lubricity oflubricant oils contained in the internal combustion engine by operatingthe internal combustion engine with a fuel comprising an effectiveamount of at least one polyalkylene glycol of formula I.
 4. The methodof claim 1, wherein A is a mixture of two different types of alkylenegroups A¹ and A², A¹ is one or more C₃- to C₇-alkylene groups, A² is oneor more C₈- to C₂₀-alkylene groups, and A¹ and A² are arranged randomlyor blockwise.
 5. The to method of claim 1, wherein A is a C₈- toC₂₀-alkylene group (A²) or a mixture of C₈- to C₂₀-alkylene groups (A²)arranged randomly.
 6. The method of claim 1, wherein the polyalkyleneglycol of formula I is prepared by a process comprising: alkoxylating apolyethylene glycol of formula IIHO—(CH₂CH₂—O)_(m)—H  (II) with a C₃- to C₂₀-alkylene oxide or a mixturethereof, thereby obtaining an alkoxylation product, wherein: m is anumber of from 2 to 100, a molar ratio of the polyethylene glycol offormula II to the C₃- to C₂₀-alkylene oxide or the mixture thereof isfrom 1:2 to 1:200, and the alkoxylation product is arranged randomly orblockwise.
 7. A fuel composition, comprising, in a major amount, agasoline fuel, and in a minor amount, at least one polyalkylene glycolof formula IHO—(A—O)_(p)—(CH₂CH₂—O)_(m)—(A—O)_(q)—H  (I) and at least one fueladditive which is different from the polyalkylene glycol and hasdetergent action, wherein A is a C₃- to C₂₀-alkylene group or a mixturethereof, m is a number of from 2 to 100, and p and q are each numbers offrom 1 to
 100. 8. The fuel composition of claim 7, wherein the at leastone fuel additive which is different from the polyalkylene glycol andhas detergent action is at least one representative (D) selected fromthe group consisting of: (Da) a mono- or polyamino group comprising upto 6 nitrogen atoms with at least one nitrogen atom having basicproperties; (Db) a nitro group, optionally in combination with ahydroxyl group; (Dc) a hydroxyl group in combination with a mono- orpolyamino group with at least one nitrogen atom having basic properties;(Dd) a carboxyl group, an alkali carboxylate, or an alkaline earthcarboxylate; (De) a sulfonic acid group, an alkali sulfonic acid salt,or an alkaline earth sulfonic acid salt; (Df) a polyoxy-C₂-C₄-alkylenemoiety terminated by a carbamate group, a hydroxyl, group, or a mono- orpolyamino, group with at least one nitrogen atom having basicproperties; (Dg) a carboxylic ester group; (Dh) a moiety derived fromsuccinic anhydride and comprising at least one of a hydroxyl group, anamino group, an amido group, and an imido group; and (Di) a moietyobtained by Mannich reaction of substituted phenols with aldehydes andmono- or polyamines.
 9. The fuel composition of claim 7, furthercomprising, a carrier oil as an additional fuel additive in a minoramount.
 10. The fuel composition of claim 7, further comprising,tertiary hydrocarbyl amine of formula NR¹R²R³ as an additional fueladditive in a minor amount, wherein R¹, R² and R³ are each independentlya C₁- to C₂₀-hydro-carbyl residue with the proviso that an overallnumber of carbon atoms in formula NR¹R²R³ does not exceed
 30. 11. Thefuel composition of claim 7, comprising: a representative (Da), which isa polyisobutene mono- or polyamine having M_(n) of from 300 to 5000,comprising at least 50 mol-% of vinylidene double bonds and prepared byhydroformylation of a polyisobutene and subsequent reductive aminationwith ammonia, a monoamine or a polyamine, and a mineral or syntheticcarrier oil.
 12. An additive concentrate, comprising: a polyalkyleneglycol of formula I:HO—(A—O)_(p)-(CH₂CH₂—O)_(m)—(A—O)_(q)—H  (I) and a fuel additive whichis different from the poly-alkylene glycol and has detergent action,wherein A is a C₃- to C₂₀-alkylene group or a mixture thereof, m is anumber of from 2 to 100, and p and q are each numbers of from 1 to 100.13. The additive concentrate of claim 12, comprising: a representative(Da), which is a polyisobutene mono- or polyamine having M_(n) of from300 to 5000, comprising at least 50 mol-% of vinylidene double bonds andprepared by hydroformylation of a polyisobutene and subsequent reductiveamination with ammonia, a monoamine or a polyamine, and a mineral orsynthetic carrier oil.